Patties of ground food material, such as ground beef and the like, can be molded automatically by machines feeding a supply of pressurized material into a mold cavity in a mold plate. In certain applications, as with ground beef and the like, it is desired to provide a patty having a predetermined density. Preferably, the density of the patty should be sufficient to provide the requisite shape-holding capability so that the patty does not fall apart during subsequent handling. However, it is also desirable to provide a patty that cooks quickly and uniformly and that has a sufficient void space to function as a reservoir for the cooking juices.
To meet these objectives with ground meat, it is desirable to reduce as much as possible the frictional forces on the surface of the meat during the feeding of the meat into the mold cavity. Surface forces can align the meat tissue in one direction and this will cause the patty to contract during cooking along the alignment direction more than in the transverse direction. This results in a cooked patty shape different than the original molded shape.
Attempts have been made over the years to produce a patty having the desired molded characteristics. Some such attempts have incorporated a process of forcing the plastic food material first through a restricted orifice region to form a thin ribbon and then into a larger volume mold cavity. The plastic food material expands outwardly into the larger mold cavity and forms a patty having a certain void capacity characteristic. An example of an apparatus for producing such a patty is that shown in the U.S. Pat. No. 4,118,831 to Holly et al.
Machines have been constructed and operated in accordance with the general principles taught by the above-identified Holly et al. patent. It is believed that, though such machines produce patties of ground meat with reduced tissue alignment, such machines are not without drawbacks.
For example, such machines typically include a cover plate with a concave tongue portion slidably disposed in a recessed top surface portion of the mold plate as illustrated in the Holly et al. patent. In the filling position, the cover plate is retracted in the mold plate recess to provide a passageway from the fill orifice in the fill plate to the mold plate mold opening. The forward edge of the fill plate fill opening is typically arcuate as is the forward edge of the cover plate tongue portion. However, the radius of the forward edge of the fill plate fill opening is typically greater than the radius of the forward edge of the cover plate tongue.
When the cover plate is retracted in the fill position, the meat is forced into the mold opening. Subsequently, the cover plate is moved forward to bring the forward edge of the cover plate tongue into registry with the mold plate mold opening. Thus, meat lying ahead of the cover plate tongue is forced into the mold opening and increases the density of the patty.
Additionally, since the radius of the curvature of the forward edge of the cover plate tongue is less than the forward edge of the overlying fill plate fill hole, meat tends to be compressed at both lateral side regions of the concave cover plate tongue below the larger radius forward edge of the overlying fill opening. This trapped meat is further squeezed into the patty in the mold opening. This tends to cause meat that has already been formed into the center part of the patty in the mold opening to be forced back outwardly to the edge of the patty and back up into the fill hole--at least until the cover plate tongue is moved completely into registry with the mold opening.
This is an undesirable "backflow" of meat from the formed patty and can cause additional working of the meat, which is undesirable. Further, the extra compression of the additional meat at both lateral side regions of the concave tongue of the cover plate can adversely affect the cooked shape of the patty, as well as the patty cooking time.
Although patties of ground beef produced with apparatus according to the teachings of the above-mentioned Holly et al. patent are an improvement over earlier prior art patties, there is a need for patties which are even lighter and fluffier, which cook more uniformly and more quickly, which retain more cooking juices, and which yield a greater cooked patty volume for a given amount of meat.
It would be desirable to provide a method and apparatus for producing a light, fluffy patty of plastic food material. It would be desirable to provide an apparatus and method especially adapted for use with ground beef and the like to produce a patty which cooks rapidly and quickly and which retains relatively large amounts of cooking juices.
Further, it would be desirable to provide such an apparatus having a relatively simple mold cavity and molding mechanism. Additionally, it would be beneficial if such a mold apparatus had a construction that is not easily susceptible to being plugged with the plastic food material. Further, such an apparatus should be simple to operate and easy to clean. This is especially desirable in those environments where such an apparatus would be used by generally unskilled labor, such as in fast food franchise restaurants and the like.